Field of the Invention
The present invention relates to a wavelength conversion member, as well as a backlight unit and a liquid crystal display device including the wavelength conversion member.
Discussion of the Background
Use of flat panel display such as a liquid crystal display device (hereinafter, also referred to as “LCD”) has been enlarged year by year as a space-saving image display device because of small power consumption. The liquid crystal display device is constituted of at least a backlight and a liquid crystal cell, and usually, further includes a polarizing plate on a backlight side, a polarizing plate on a viewing side.
In the flat panel display market, the enhancement of color reproduction is being developed as an improvement of the LCD performance. With regard to this point, in recent years, a Quantum Dot (QD, also referred to as quantum point) as a light emitting material has drawn many people's attention (see JP2013-544018A, which is expressly incorporated herein by reference in its entirety). For example, when exciting light enters a wavelength conversion member containing quantum dots from a backlight, the quantum dots are excited to emit fluorescence. By using quantum dots having different light emission characteristics, emission of red light, green light and blue light can be achieved to thereby embody white light. Since the fluorescence emitted by quantum dots has a small half width, the obtained white light has a high brightness and is excellent in color reproducibility. Due to the advancement of the three wavelength light source technique using such quantum dots, the range of color reproducibility is enlarged from 72% to 100% in terms of the present TV standard ratio (FHD (Full High Definition)), NTSC (National Television System Committee)).